Dust mite allergy

Dust mite allergy is an allergic reaction to tiny bugs that commonly live in house dust. Signs of dust mite allergy include those common to hay fever, such as sneezing and runny nose. Many people with dust mite allergy also experience signs of asthma, such as wheezing and difficulty breathing.

Dust mites, close relatives of ticks and spiders, are too small to see without a microscope. Dust mites eat skin cells shed by people, and they thrive in warm, humid environments. In most homes, such items as bedding, upholstered furniture and carpeting provide an ideal environment for dust mites.

By taking steps to reduce the number of dust mites in your home, you may get control of dust mite allergy. Medications or other treatments are sometimes necessary to relieve symptoms and manage asthma.

Dust mite allergy symptoms caused by inflammation of nasal passages include:

• Sneezing
• Runny nose
• Itchy, red or watery eyes
• Nasal congestion
• Itchy nose, roof of mouth or throat
• Postnasal drip
• Cough
• Facial pressure and pain
• Swollen, blue-colored skin under your eyes
• In a child, frequent upward rubbing of the nose

If your dust mite allergy contributes to asthma, you may also experience:

• Difficulty breathing
• Chest tightness or pain
• An audible whistling or wheezing sound when exhaling
• Trouble sleeping caused by shortness of breath, coughing or wheezing
• Bouts of coughing or wheezing that are worsened by a respiratory virus such as a cold or the flu

A dust mite allergy can range from mild to severe. A mild case of dust mite allergy may cause an occasional runny nose, watery eyes and sneezing. In severe cases, the condition may be ongoing (chronic), resulting in persistent sneezing, cough, congestion, facial pressure, an eczema flare-up or severe asthma attack.

Some signs and symptoms of dust mite allergy, such as a runny nose or sneezing, are similar to those of the common cold. Sometimes it's difficult to know whether you have a cold or an allergy. If symptoms persist for longer than one week, you might have an allergy.

If your signs and symptoms are severe — such as severe nasal congestion, wheezing or difficulty sleeping — call your doctor. Seek emergency care if wheezing or shortness of breath rapidly worsens or if you are short of breath with minimal activity.

Allergies occur when your immune system reacts to a foreign substance such as pollen, pet dander or dust mites. Your immune system produces proteins known as antibodies that protect you from unwanted invaders that could make you sick or cause an infection.

When you have allergies, your immune system makes antibodies that identify your particular allergen as something harmful, even though it isn't. When you come into contact with the allergen, your immune system produces an inflammatory response in your nasal passages or lungs. Prolonged or regular exposure to the allergen can cause the ongoing (chronic) inflammation associated with asthma.

Dust mites eat organic matter such as skin cells people have shed, and rather than drinking water, they absorb water from humidity in the atmosphere.

Dust also contains the feces and decaying bodies of dust mites, and it's the proteins present in this dust mite "debris" that are the culprit in dust mite allergy.

The following factors increase your risk of developing a dust mite allergy:

• Having a family history of allergies. You're more likely to develop a sensitivity to dust mites if several members of your family have allergies.
• Exposure to dust mites. Being exposed to high levels of dust mites, especially early in life, increases your risk.
• Being a child or a young adult. You're more likely to develop dust mite allergy during childhood or early adulthood.

If you have a dust mite allergy, exposure to the mites and their debris can cause complications.

• Sinus infections. Ongoing (chronic) inflammation of tissues in the nasal passages caused by dust mite allergy can obstruct your sinuses, the hollow cavities connected to your nasal passages. These obstructions may make you more likely to develop infections of the sinuses (sinusitis).
• Asthma. People with asthma and dust mite allergy often have difficulty managing asthma symptoms. They may be at risk of asthma attacks that require immediate medical treatment or emergency care.